1. Field of the Invention
This invention relates to a straddle type vehicle such as a motorcycle, for example.
2. Description of Related Art
Conventionally, in straddle type vehicles such as motorcycles etc., some vehicles are known to include a structure that has a single rear cushion unit, i.e., the so-called mono suspension structure as a rear cushion unit (for example, see following Patent Document 1).
The motorcycle disclosed in following Patent Document 1 includes a main frame obliquely extending downward rearward from a head pipe, and a pair of a right and a left seat rail obliquely extending upward rearward from a rear portion of the main frame. A fuel tank is mounted on the seat rails to be positioned under a seat. A rear wheel is supported by a rear end of a rear arm extending in a fore to aft direction. A front end of the rear arm is supported by a pivot shaft for swinging. A cross pipe extends between the right and left seat rails. This cross pipe has a cushion bracket. A top end of the rear cushion is coupled with the cushion bracket, while a bottom end of the rear cushion is coupled with a lower portion of a middle section of the rear arm in the fore to aft direction via a bracket. The rear cushion is entirely positioned below the fuel tank.
[Patent Document 1] JP-A-2002-37169, laid-open application publication
However, in the motorcycle described above, if the rear cushion extends along a locus of the pivotal movement of the rear arm about an axis of the pivot shaft so as to improve the suspension performance, a slant angle of the rear cushion needs to be small, and the rear cushion needs to extend generally vertically to be attached. Thus, a space defined under the seat is inevitably small to restrict layout under the seat.
Also, in the motorcycle described above, the depth of the fuel tank cannot be designed to be larger because it is needed to ensure below the fuel tank a mount space for the rear cushion. Therefore, in order to ensure a necessary capacity of the fuel tank, the fuel tank needs to be elongated in the fore to aft direction or in a transverse direction. Thus, the layout under the seat is restricted by the large area size of the fuel tank in a top plan view.